Ethane, 2-bromo-1,1-diethoxy-

UsesSynthetic building block1,2

UsesBromoacetaldehyde diethyl acetal, is used as a synthetic building block. It is mainly used for synthesis of antibiotics such as erythromycin and cephalosporins and to other drugs. It also can be used as pharmaceutical intermediates. Besides, this chemical can be used to pruduce drugs such as methylthio imidazole, chlorpheniramine and others for thyroid. It also acts as a Useful intermediate for the preparation of other -heterosubstituted acetaldehyde acetals.

General DescriptionMay darken in storage

PreparationTo a flask containing 118.0 gm (1.0 mole) of diethyl acetal and 55 gm (0.55 mole) of calcium carbonate is dropwise added 55 ml (1.0 mole) of bromine over a 30-45 min period while keeping the reaction temperature at 5°-10°C. The reaction mixture is allowed to stand 24 hr, steam is introduced to dissolve the salts, the oil separated, dried over potassium carbonate, and distilled to afford 61-83 gm (31-42%), b.p. 167°-170°C. The product is further purified by shaking with potassium carbonate and distilling it under reduced pressure, b.p. 48°-49°C (3 mm Hg). The pure acetal is unstable and becomes colored in a few hours and black after several days. However, the crude acetal boiling at 167°-170°C is stable for several months.